One embodiment of this invention provides an apparatus for disconnecting and reconnecting an external device to or from a computer having a key of keyboard, key-like button in anv location in the computer system and internal software process recognizing specific patterns of key strokes resulting from distinctive software capability. The methods provide for the direct identification of compound structure following combinatorial synthesis using molecular mass measurements of individual compounds, thereby eliminating the necessity of encoding synthetic steps. This arrangement makes it possible to provide a highly versatile Doppler type ultrasonic flowmeter that permits simple, easy, contactless, precise and highly accurate measurement of the flow rates of fluids to be measured that are flowing in various fluid pipes. The method and apparatus is particularly suitable for converting a Non-Return-to-Zero data signal to a Return-to-Zero data signal by modulating the Non-Return-to-Zero data signal with a Return-to-Zero pulse signal. A bottom cover portion of the cover element covers an opening portion. In comparison to known aryloxyalinine derivative in vivo imaging agents, the in vivo imaging agent of the present invention has better properties for in vivo imaging.